Most exercises tend to develop a large number of muscle groups so that those muscles can better perform that exercise in the future. However, sometimes certain muscles need to be developed further for asthetic reasons or because those muscles may be needed for other purposes. In such instances, exercises which predominately develop only those selected muscles have been desired. Other times, selective exercises have been used to exercise certain selected muscles in order to avoid stressing other parts of the body. For example, a person with a back injury may want to engage in exercises that develop his forearms without placing stress on his back.
U.S. Pat. No. 3,982,755 teaches a specially shaped cylindrical rod having two inverted, tapered, generally cone-shaped sections joined together at their narrowest sections, generally in the middle of the rod, about which a rope may be wrapped with the free end of the rope attached to a weight. By standing erect and holding the rod in both hands, a person can raise or lower the weight by twisting the rod to wind the rope onto the cylinder. According to this patent, this device is "designed to deepen the chest, broaden the waist and reduce the waistline of the user." Definitely, such a device would utilize the arm, shoulder, back and abdominal muscles without selectively exercising any one of them.